Data Storage Devices (DSDs) are often used to record data onto or to reproduce data from a storage media. One type of storage media includes a rotating magnetic disk, such as in a Hard Disk Drive (HDD). In such DSDs, a head is positioned in relation to a disk to magnetically read and write data in tracks on a surface of the disk.
The amount of data that can be stored on a disk in a given area (i.e., an areal density) generally continues to increase with each new generation of DSDs that use a disk to store data. In some cases, some or all of the tracks on a disk may be written as overlapping tracks with Shingled Magnetic Recording (SMR) as a way of increasing the number of Tracks Per Inch (TPI) on the disk by making the tracks narrower. SMR increases TPI by using a relatively wide shingle write head with a stronger magnetic field to overlap tracks like roof shingles. The non-overlapping portion then serves as a narrow track that can be read by a narrower read head. However, the overlapping of tracks in an SMR zone means that previously written data cannot be modified or rewritten without affecting an adjacent track. SMR zones are therefore sequentially written in one radial direction (i.e., toward the inner diameter of the disk or toward the outer diameter of the disk) to avoid affecting previously written data in an adjacent track.
Some types of data may be better suited for the sequential writing of SMR than other types of data. For example, data that is not frequently modified or rewritten (e.g., cold data), such as video data for a movie file, can usually be sequentially written using SMR without having to worry about rewriting certain portions of previously written video data. On the other hand, data such as certain operating system files or data that is frequently changed as with a word processing program (e.g., hot data), may not be well suited for storage using SMR. For this reason, some disks may be formatted by the manufacturer to include a mix of Conventional Magnetic Recording (CMR) zones of non-overlapping tacks and SMR zones of overlapping tracks. The CMR zones can allow for storing data that may be randomly written or non-sequentially written, while SMR zones of overlapping tracks may be used to store data that is not frequently modified.
However, the location and number of CMR or SMR zones is generally fixed, despite the needs or data usage patterns of the DSDs in the field. Formatting of the disk into SMR and CMR zones is conventionally limited to being performed by the manufacturer at the factory since changing the formatting of the disk between SMR and CMR would change the storage capacities and addressing of sectors on the disk.